Kye Min Kim

Pharmacokinetics and pharmacodynamics of propofol microemulsion and lipid emulsion after an intravenous bolus and variable rate infusion.

Background:The aim of this trial was to evaluate the induction and recovery characteristics of microemulsion propofol (Aquafol; Daewon Pharmaceutical Co., Ltd., Seoul, Korea). Pharmacokinetics, pharmacodynamics, and safety profile were investigated. Lipid emulsion propofol (Diprivan®; AstraZeneca, London, United Kingdom) was used as a comparator. Methods:Thirty-one healthy volunteers aged 20–79 yr were given an intravenous bolus of propofol 2 mg/kg, followed by variable rate infusion for 60 min. Each volunteer was studied twice with different formulations at an interval of 1 week. Arterial concentrations of propofol were measured, and Bispectral Index was used as a surrogate measure of propofol effect. The induction and recovery characteristics including bioequivalence were evaluated by noncompartmental analysis. The pharmacokinetics and pharmacodynamics were investigated using a population approach with mixed effects modeling. The rate, severity, and causal relation of adverse events were analyzed. Results:Both formulations were bioequivalent. The observed time to peak effect after a bolus of both formulations was 1.5 min. Plasma concentration of propofol at loss of consciousness, time to loss of consciousness after a bolus, and time to recovery of consciousness after discontinuation of infusion did not show significant differences. The population pharmacokinetics and pharmacodynamics revealed a variety of differences between two formulations. Aquafol showed similar safety profile to Diprivan®. Conclusions:The efficacy and safety of Aquafol were not different from those of Diprivan® within the dose range in this study.

Effective dose of dexmedetomidine to induce adequate sedation in elderly patients under spinal anesthesia

Background During sedation with dexmedetomidine, a dose adjustment may be needed based on the invasiveness of the procedure, the patients general condition, and their age. We aim here to determine the effective dose (ED) of dexmedetomidine to induce an adequate depth of sedation in elderly patients undergoing spinal anesthesia. Methods In this study, 47 patients aged 65 years or older, American Society of Anesthesiologists physical status I or II, undergoing spinal anesthesia were included. Patients were randomly allocated into group I, II, III, IV or V according to the dexmedetomidine loading dose of 0.1, 0.3, 0.5, 0.7 and 1.0 µg/kg, respectively. After spinal anesthesia, the assigned loading dose of dexmedetomidine was infused intravenously for 10 minutes, after which infusion was maintained at a rate of 0.3 µg/kg/h for the next 10 minutes in all groups. We assessed the depth of sedation with the Ramsay sedation scale every five minutes and measured vital signs and the oxygen saturation. The ED50 and ED95 of dexmedetomidine to obtain adequate sedation (Ramsay sedation score ≥ 3) upon the completion of the loading dose were calculated with logistic regression. Results The ED50 and ED95 of dexmedetomidine for adequate sedation were 0.29 µg/kg (95% confidence intervals [CI] 0.14-0.44) and 0.86 µg/kg (95% CI 0.52-1.20), respectively. Hypotension was frequent in groups IV, V compared to groups I, II, III (31.6 vs. 3.6%, P = 0.013). Conclusions ED95 of dexmedetomidine loading dose for adequate sedation is 0.86 µg/kg. However, dose higher than 0.5 µg/kg can lead to hemodynamic instability.

Risk factors associated with outcomes of hip fracture surgery in elderly patients.

Background Hip fracture surgery on elderly patients is associated with a high incidence of morbidity and mortality. The aim of this study is to identify the risk factors related to the postoperative mortality and complications following hip fracture surgery on elderly patients. Methods In this retrospective study, the medical records of elderly patients (aged 65 years or older) who underwent hip fracture surgery from January 2011 to June 2014 were reviewed. A total of 464 patients were involved. Demographic data of the patients, American Society of Anesthesiologists physical status, preoperative comorbidities, type and duration of anesthesia and type of surgery were collected. Factors related to postoperative mortality and complications; as well as to intensive care unit admission were analyzed using logistic regression. Results The incidence of postoperative mortality, cardiovascular complications, respiratory complications and intensive care unit (ICU) admission were 1.7, 4.7, 19.6 and 7.1%, respectively. Postoperative mortality was associated with preoperative respiratory comorbidities, postoperative cardiovascular complications (P < 0.05). Postoperative cardiovascular complications were related to frequent intraoperative hypotension (P <0.05). Postoperative respiratory complications were related to age, preoperative renal failure, neurological comorbidities, and bedridden state (P < 0.05). ICU admission was associated with the time from injury to operation, preoperative neurological comorbidities and frequent intraoperative hypotension (P < 0.05). Conclusions Adequate treatment of respiratory comorbidities and prevention of cardiovascular complications might be the critical factors in reducing postoperative mortality in elderly patients undergoing hip fracture surgery.

Factors that influence awakening in coronary artery bypass graft using propofol and remifentanil

BACKGROUND The development of total intravenous anesthesia in coronary artery bypass graft (CABG) surgery has led to increased interest in the use of combination of propofol and remifentanil. Early extubation in post-cardiac surgery reduces the length of stay in intensive care unit and hospital and costs. The purpose of this study is to evaluate which anesthetic factors affect awakening time after anesthesia. METHODS We enrolled twenty patients of ASA physical status II or III, scheduled for CABG in this study. All patients received a standardized propofol/remifentanil anesthesia as an effect site target controlled infusion. We recorded times to awakening and tracheal extubation, duration of cardiopulmonary bypass (CPB) period, total time of anesthesia and operation. Also, we recorded dose of propofol, remifentanil, fentanyl and minimum body temperature during CPB. To predict the factors that affect awakening time as a dependent variable, we considered all measured parameters as independent variables, and analyzed multiple linear regressions. RESULTS The mean time responded to verbal command was 216.5 +/- 124.8 minutes after end of surgery. Among several parameters, minimum body temperature during CPB (P = 0.001) and total time of anesthesia (P = 0.003) were considered as significant factors that influence awakening time after CABG. CONCLUSIONS Minimum body temperature during CPB and the duration of anesthesia influence awakening time after CABG, significantly.